1. Field of the Invention
This invention relates to a method of revising a profile, and more particularly, to a profile revising method for revising a profile comprising specified figure elements such as points, straight lines and circles which are connected in order.
2. Description of the Related Art
In an automatic programming system for creating NC data using an automatic programming language such as APT (automatic programming tools) or FAPT,
(a) a part program based on the automatic programming language is created by defining points, straight lines and circular arcs using simple symbols (this is referred to as "figure definition"), and then defining a tool path using the defined points, straight lines and circular arcs (referred to as "motion statement definition"), and
(b) the part program based on the automatic programming language is subsequently converted into NC data comprising NC data (EIA codes or ISO codes) in a format capable of being executed by an NC unit.
For example, in the creation of a part program for moving a tool along a part profile A comprising straight lines and a circular arcs shown in FIG. 10(a), figure definition is performed by defining straight lines S.sub.1, S.sub.2, S.sub.3 and a circle C.sub.1 [see FIG. 10(b)] which are necessary for defining a part profile, as follows using a keyboard or tablet: EQU C.sub.1 =x.sub.o, y.sub.o, r.sub.o ( 1) EQU S.sub.1 =x.sub.1 X (2) EQU S.sub.2 =y.sub.2 Y (3) EQU S.sub.3 =y.sub.2 Y (4) EQU P.sub.1 =S.sub.1, S.sub.2 ( 5)
In the foregoing,
(1) signifies a circle of center (x.sub.o,y.sub.o) and radius r.sub.o ;
(2) signifies a straight line parallel to the Y axis and having an X-intercept whose value is x.sub.1 ;
(3) signifies a straight line parallel to the X axis and having a Y-intercept whose value is y.sub.1 ;
(4) signifies a straight line parallel to the X axis and having a Y-intercept whose value is y.sub.2 ; and
(5) signifies the point of intersection between the straight lines S.sub.1, S.sub.2.
Thereafter, the figure elements (which are displayed on a CRT screen) are picked in clockwise or counterclockwise direction in order, e.g., EQU P.sub.1 .fwdarw.S.sub.2 .fwdarw.C.sub.1 .fwdarw.S.sub.3 .fwdarw.S.sub.1
(where, with regard to the circle C.sub.1, a point on the circular arc P.sub.2 P.sub.3 is picked, with the clockwise direction serving as a reference), and the profile A [FIG. 10(a)] is defined in the manner ##STR1## It should be noted that Eq. (6) signifies a shape up to the point P.sub.3 clockwise along the circle C.sub.1.
Thereafter, machining starting and end points, etc., of the profile A are designated by motion statement definition to define a tool path along which a tool is moved.
There are cases where figure elements Ck', Sn', St' are added to a profile [e.g, profile A in FIG. 10(a)], whose figure has already been defined, to modify the profile into a new profile A' shown in FIG. 11. In such cases, the prior art is such that each figure element must be redefined from the start and figure elements must be picked in order along the profile A' to specify the profile. As a result, a problem which arises is that the revising operation requires a great amount of time.